Safety and reliability improvements of valves and actuators for the offshore oil and gas industry through optimized design

Abstract

Valves are essential components of piping systems in the oil and gas industry, especially offshore, where they are used for stopping or starting the fluid, flow regulation, and back flow prevention, as well as safety reasons. The efficiency, safety and reliability of an oil and gas plant is largely dependent on the handling and transportation of fluid through the piping system, including industrial valves. In the offshore sector of the oil and gas industry, valve failure for different reasons, such as corrosion and material failure, inadequate strength against loads, nonconformance to the international standards, etc., is a big risk, with severe negative consequences. Some of the negative impacts of valve failure in the oil and gas industry, especially the offshore sector, can be summarized as loss of asset and production and Safety and Environmental issues (HSE), including problems like environmental pollution, loss of human life in some cases and jeopardizing safety and reliability, etc. Thus, developing methods to improve the design, selection, safety and reliability of valves and actuators is essential and the main objective of this thesis. It should be noted that actuators are mechanical devices installed on the valves, and the performance of the valves is largely dependent on the actuators. The literature review mainly focuses on existing tools, including international and Norwegian standards, books and publications for piping and valves in the oil and gas industry. The key findings in the literature review are the identification of different corrosion mechanisms and material choices in the offshore industry; valve technology; applications, design and selection philosophy; different methods for systematic material selection; and International and Norwegian codes and standards for the design of piping and valves. The basic research carried out is represented by 19 published papers by the American Society of Mechanical Engineering (ASME), Springer and other American journals. Different cases related to the valves and actuators in the Norwegian offshore industry and recent projects, including the Johan Sverdrup project which I was involved in while working for AkerSolutions, have been reviewed in the submitted papers. The data analysis in most of the papers is quantitative, based on calculations and formulas given in international standards such as ASME to improve design, reliability and reduce the weight of the valves. Different key findings, such as subsea valve and actuator safety and reliability improvement through testing, optimized material selection for subsea valves, optimized valve and actuator selection, as well as valve design and weight improvements, have been included in this thesis. Keywords: Valve, Design, Material, Corrosion, Safety and reliability, Actuator, Offshore, Oil and Gas